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Gel electrophoresis of end‐labeled DNA II. Dynamics and detrapping in pulsed fields
Author(s) -
Défontaines AnneDominique,
Viovy JeanLouis
Publication year - 1994
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150150120
Subject(s) - electrophoresis , time constant , plateau (mathematics) , analytical chemistry (journal) , chemistry , range (aeronautics) , field strength , gel electrophoresis , chemical physics , materials science , molecular physics , chromatography , physics , magnetic field , mathematical analysis , biochemistry , mathematics , quantum mechanics , electrical engineering , composite material , engineering
A theory for field‐inversion gel electrophoresis of a flexible polyelectrolyte bearing an uncharged bulky label at one end is described, and the evolution of the mobility with chain length, field strength, friction of the label, and the duration of the forward and reverse pulses is predicted. A new critical size, N detrap , is introduced, and its value calculated. It increases roughly linearly with the duration of the reverse pulses. Chains smaller than N detrap are detrapped by reverse pulses, and may have a high mobility, whereas chains larger than N detrap are not trapped, and have a very small mobility. This leads to an increase of the mobility (as compared with constant field) in a given range of sizes, and to a strong selectivity around N detrap Depending on the parameters, numerous other effects, including a secondary mobility plateau and band inversion, may appear. The corresponding regimes are predicted and discussed. All predictions are qualitatively consistent with available experimental data. We use them to suggest efficient conditions for the development of pulsed‐field trapping electrophoresis, a possible tool for improved DNA sequencing. In particular, we recommend using a ramping of pulse times, with a constant ratio of forward to reverse time in the range 3 to 5.